# -*- coding: UTF-8 -*-
from typing import List
from leetcode_helper import TestcaseHelper, SolutionBase


class Solution(SolutionBase):
    # 解题的方法，命名和Leetcode的保持一致即可
    def maxLength(self, arr: List[str]) -> int:
        def str_int(s: str) -> int:
            result = 0
            for ch in s:
                bit = 1 << (ord(ch) - ord('a'))
                if result & bit == 0:
                    result |= bit
                else:
                    return 0
            return result

        def backtrack(pos: int, cur_mask: int) -> None:
            nonlocal bit_masks
            if pos == len(bit_masks):
                nonlocal ans
                ans = max(bin(cur_mask).count("1"), ans)
                return

            str_bit = bit_masks[pos]

            if str_bit != 0 and str_bit & cur_mask == 0:
                backtrack(pos + 1, cur_mask|str_bit)

            backtrack(pos + 1, cur_mask)

        ans = 0
        bit_masks = []
        for s in arr:
            bit_masks.append(str_int(s))

        backtrack(0, 0)
        return ans


if __name__ == '__main__':
    solution = Solution()

    # 按照leetcode的题目说明，将基本的test case填入
    # 每条case的最后一个元素是正确的结果，即期待的结果
    # 使用元组来保存输入的数据，期待的结果
    testcases = [
        (["zog", "nvwsuikgndmfexxgjtkb", "nxko"], 4),
        (["yy", "bkhwmpbiisbldzknpm"], 0),
        (["cha", "r", "act", "ers"], 6),
        (["un", "iq", "ue"], 4),
        (["abcdefghijklmnopqrstuvwxyz"], 26),
        (["a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p"], 16)
    ]

    for case_item in testcases:
        # 获取测试用的case和期待的执行结果
        input1 = case_item[0]

        expect = case_item[len(case_item) - 1]

        exec_result = solution.maxLength(input1)

        # 判断执行结果，输出提示信息
        check_result = solution.check_result(expect, exec_result)
        TestcaseHelper.print_case(check_result, case_item, exec_result)
